Weed pressure, nutrient content, and seed yield in field grown sulfonylurea-resistant Camelina sativa and Brassica napus

Authors: Anderson, James; Bigger, Brant; HOWATT, KIRK - North Dakota State University; METTLER, JOSEPH - North Dakota State University; BERTI, MARISOL - North Dakota State University

Submitted to: Agronomy
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/21/2022
Publication Date: 11/2/2022
Citation: Anderson, J.V., Bigger, B., Howatt, K., Mettler, J., Berti, M.T. 2022. Weed pressure, nutrient content, and seed yield in field grown sulfonylurea-resistant Camelina sativa and Brassica napus. Agronomy. 12(11). Article 2622. https://doi.org/10.3390/agronomy12112622.
DOI: https://doi.org/10.3390/agronomy12112622

Interpretive Summary: Camelina is an important oilseed species in the mustard family, which includes canola. However, the lack of approved herbicides for weed control in camelina has limited its expansion as a commercial crop. To evaluate weed suppression, nutrient retention, and seed yield in non-transgenic sulfonylurea-resistant camelina and canola, a study was conducted in 2020 at two replicated field sites near Fargo, North Dakota. At both field sites, sulfonylurea-resistant camelina and canola were treated with or without sulfonylurea herbicide and weed suppression was compared with untreated fallow controls. Sulfonylurea-resistant camelina and canola alone reduced late-season dry weight biomass of weeds by > 75% and = 60%, respectively, compared with fallow plots. Mid-season treatment with sulfonylurea herbicide did not significantly reduce weed pressure over that of untreated crop but, in some cases, herbicide treatment had an additive effect on further reducing weed pressure. Additionally, application of sulfonylurea herbicide had little impact on altering crop biomass, seed yield, or nutrient retention over that of the untreated crop. Outcomes from this study suggest that sulfonylurea-resistant camelina and canola should provide additional options for improving integrated weed management approaches, and for reducing nutrient leaching and herbicide application rates in the upper Midwest and northern Great Plains of the U.S.A.

Technical Abstract: Camelina (Camelina sativa (L.) Crantz], an oilseed species of Brassicaceae, does not have approved herbicides for weed control, which limits its expansion as a commercial crop. To evaluate agronomic traits and ecosystem services of non-transgenic cultivars of sulfonylurea-resistant camelina and canola (Brassica napus L.), a field study was conducted near Fargo, North Dakota. Two replicated locations (NDSU and NW22) were set up in a randomized complete block design including four blocks of camelina, canola, and fallow per location. Camelina and canola were seeded (18 May) at 4.9 and 2.9 kg ha-1, respectively, using 19-cm row spacing. Data was collected mid- and late-season (29 June and 22 July, respectively) for crop and weed stem count (no. m-2), biomass dry matter (kg m-2), and nutrient (N, P, K, S) content (kg ha-1), as-well-as final season (7 August) seed yield (kg ha-1) for camelina and canola treated with and without sulfonylurea. Using Prefer 90 (NIS) at 0.25% v/v, camelina was treated with thifensulfuron at 6.3 g a.i. ha-1, and canola was treated with thifensulfuron at 10.5 g a.i. ha-1 and tribenuron at 5.3 g a.i. ha-1. Sulfonylurea-resistant camelina and canola reduced late-season dry weight biomass of weeds by > 75% and = 60%, respectively, compared with fallow plots. Application of sulfonylurea herbicides to camelina or canola prior to mid-season analyses was not a significant factor (P=0.05) for reducing weed pressure and generally had little impact on altering crop biomass, seed yield, and nutrient retention. However, in some cases, herbicide treatment had an additive effect of reducing weed pressure over that of camelina or canola alone. Depending on the rotational cropping system, sulfonylurea-resistant camelina and canola should provide additional options for improving integrated weed management approaches and reducing nutrient leaching in the upper Midwest and northern Great Plains of the U.S.A.